coup

a sudden, violent, and illegal seizure of power from a government

"he was overthrown in an army coup"

synonyms:

seizure of power · overthrow · takeover · ousting · deposition

There's another meaning of "denial" in psychoanalytic theory: A psychological defense we all use at times to reduce our anxiety when something feels particularly disturbing.

Finally, there is a particular type of "denial" we are witnessing nowadays: When seemingly intelligent and sane adults vehemently deny truths despite a body of irrefutable data.